decision – Ugly output with openGL

I simply began to check openGL and I wrote this “Hey World” program to attract a triangle.

#embody 

int important(void)
{
    GLFWwindow* window;

    /* Initialize the library */
    if (!glfwInit())
        return -1; 

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 640, "Hey World", NULL, NULL);
    if (!window)
    {
        glfwTerminate(); 
        return -1;
    }

    /* Make the window's context present */
    glfwMakeContextCurrent(window);
    
    /* Loop till the person closes th e window */
    whereas (!glfwWindowShouldClose(window)) 
    {

        /* Render right here */
        glClear(GL_COLOR_BUFFER_BIT);

        glBegin(GL_TRIANGLES);
        glVertex2f(-0.5f, -0.5f);
        glVertex2f( 0.0f,  0.5f); 
        glVertex2f( 0.5f, -0.5f);
        glEnd();

        /* Swap back and front buffers */
        glfwSwapBuffers(window);

        /* Ballot for and course of occasions */
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}

The issue is that I do not just like the output because it appears to not match the decision of my display. The next photos evaluate the output that I receive by operating the code above and a reproduction that I draw utilizing inkscape.

As you may see, the diagonal edges of the triangle generated with openGL should not as clean as those of the triangle generated with inkscape. I am surprise if there’s a approach to repair this drawback. Be aware that I am an absolute newbie, in order that I am not a lot within the answer, however moderately I simply wish to know if sooner or later I will repair the issue.